Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

JavaScript JavaScript and the DOM (Retiring) Getting a Handle on the DOM Practice Selecting Elements

Jason Pallone
Jason Pallone
11,340 Points
Posted by Jason Pallone
Jason Pallone
11,340 Points

Can someone help me understand this please?

So I know the answers to the challenge that's not the issue, the issue is why, like for the galleryLinks = document.querySelectorAll('gallery li a')

why is that it why don't i need to put 'img' and 'p' as well inside the parenthesis?

Then for the last one with footer, why do I need to put 'img' in there but not in gallery?

Can someone just kind of break it down for me please how it works?

Thank you!

js/app.js 
let navigationLinks;
let galleryLinks;
let footerImages;

navigationLinks = document.querySelectorAll('nav a')
galleryLinks   = document.querySelectorAll('#gallery li a')
footerImages  = document.querySelectorAll('footer a img')
index.html 
<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title>Nick Pettit | Designer</title>
    <link rel="stylesheet" href="css/normalize.css">
    <link href='http://fonts.googleapis.com/css?family=Changa+One|Open+Sans:400italic,700italic,400,700,800' rel='stylesheet' type='text/css'>
    <link rel="stylesheet" href="css/main.css">
    <link rel="stylesheet" href="css/responsive.css">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
  </head>
  <body>
    <header>
      <a href="index.html" id="logo">
        <h1>Nick Pettit</h1>
        <h2>Designer</h2>
      </a>
      <nav>
        <ul>
          <li><a href="index.html" class="selected">Portfolio</a></li>
          <li><a href="about.html">About</a></li>
          <li><a href="contact.html">Contact</a></li>
        </ul>
      </nav>
    </header>
    <div id="wrapper">
      <section>
        <ul id="gallery">
          <li>
            <a href="img/numbers-01.jpg">
              <img src="img/numbers-01.jpg" alt="">
              <p>Experimentation with color and texture.</p>
            </a>
          </li>
          <li>
            <a href="img/numbers-02.jpg">
              <img src="img/numbers-02.jpg" alt="">
              <p>Playing with blending modes in Photoshop.</p>
            </a>
          </li>
        </ul>
      </section>
      <footer>
        <a href="http://twitter.com/nickrp"><img src="img/twitter-wrap.png" alt="Twitter Logo" class="social-icon"></a>
        <a href="http://facebook.com/nickpettit"><img src="img/facebook-wrap.png" alt="Facebook Logo" class="social-icon"></a>
        <p>&copy; 2016 Nick Pettit.</p>
      </footer>
    </div>
  <script src="js/app.js"></script>
  </body>
</html>

1 Answer

Steven Parker
Steven Parker
231,269 Points
Steven Parker
Steven Parker
231,269 Points

In a descendant selector, you typically provide a container and target. It's rarely necessary to provide anything in between. So "#gallery li a" is already more specific than needed, "#gallery a" would do (literally "all links in the #gallery").

Similarly, "footer img" is enough for the final task ("images in the footer"). While those images might also happen to be inside links (a), it's not necessary to include that part in the selector.

And "img" wasn't needed for task 2 because the target for that one was the links themselves (with or without images).